Hydraulic distribution valves



Jan. 11, 1966 T. SHERWEN 3,228,304

HYDRAULI C DI STRIBUTION VALVES Filed April 25, 1963 3 Sheets-Sheet 1Jan. 11, 1966 Filed April 25, 1963 T. SHERWEN HYDRAULIC DISTRIBUTIONVALVES 5 Sheets-Sheet 2 Jan. 11, 1966 T. SHERWEN 3,228,304

HYDRAULIC DISTRIBUTION VALVES Filed April 25, 1963 3 SheetsSheet :5

United States Patent 3,228,304 HYDRAULIC DISTREBUTEUN VALVES TheoSherwen, Yew lorch, Minchinhanipton, Gloucestershire, England, assignorto Prime Movers (Wiltsh re) Limited, Yew Porch, Minehinhampton,Gloucestershire, England, a British company Filed Apr. 25, 1963, Ser.No. 275,6?4 Claims priority, application Great Britain May 4, 1962,17,268/ 62 Claims. (Cl. 91204) This invention relates to hydraulicdistribution valves for sequentially connecting pressure and exhaustports in a stator with flow and return ports in a co-operating rotor,and is mainly concerned with simplifying the construction of suchvalves.

Accordingly, the invention provides a hydraulic distribution valveincluding a stator block having pressure and exhaust ports openingtherethrough in-to opposed arcuate recesses in one block face, a rotorarranged for rotatable mounting relative to the stator with one faceoverlying the recessed face of said stator block and having portstherethrough with openings in said overlying face positioned to registeralternately with said stator recesses during relative rotation of therotor, and sealing means interposed between said overlying stator androtor faces to provide substantially sealed connections between therespective stator recesses and the rotor ports.

Such a valve is particularly, though not exclusively, suitable for usein a vehicle wheel driven by a hydraulic motor built-in to the wheelhub. Accordingly, the invention further provides, in a vehicle wheelhaving a hub with a built-in hydraulic multi-cylinder driving motormounted for rotation on a relatively non-rotary cam shaft, a hydraulicdistribution valve including a stator block which is secured to theouter end of said cam shaft and has pressure and exhaust portsconnecting with pressure and exhaust passages formed through the camshaft and opening into opposed arcuate recesses in an outer block face,a rotor mounted on said wheel hub with one ported face overlying therecessed face of said stator block, the ports in said overlying rotorface being positioned to register alternately with said stator recessesduring rotation of the rotor and being connected with flow and returnpassages leading to the respective cylinders of the motor, and sealingmeans interposed between said overlying stator and rotor faces toprovide substantially sealed connections between the respective statorrecesses and the rotor ports.

In order that the invention may be clearly understood and readilycarried into effect, two embodiments thereof will now be described indetail with reference to the accompanying drawings, in which:

FIGURE 1 is a side elevational view showing the hub of a vehicle wheelhaving a built-in hydraulic motor supplied with fluid through ahydraulic distribution valve of the invention,

FIGURE 2 is an outline side view of the wheel hub shown in FIGURE 1 withpart of the distribution valve and part of a cam shaft, on which the hubis mounted, shown in cross-section,

FIGURE 3 is a sectional view, to an enlarged scale and partially brokenaway, showing details of the hydratilic distribution valve embodied inFIGURES 1 and 2,

FIGURE 4 is a sectional view of the valve stator block taken'on the lineIV-IV of FIGURE 3,

FIGURE 5 is a further sectional view of the stator block taken on theline VV of FIGURE 4,

FIGURE 6 is a side elevational view showing part of a slightly modifiedvehicle wheel hub fitted with an alternative form of hydraulicdistribution valve in accordance with the invention,

FIGURE 7 is a cross-sectional view corresponding to FIGURE 6, and

FIGURES 8, 9 and 10 show respectively a top view, a side view and afront view of the stator block employed in the hydraulic distributionvalve embodied in FIG- URES 6 and 7.

In the drawings, FIGURES l to 5 show a hydraulic distribution valve foruse on the hub of a road or ground wheel of a vehicle having a built-inhydraulic motor. To accommodate the motor, the wheel has a rotary hubcasing 1 which is intended to carry the wheel rim (not shown) and ismounted on a non-rotary or relatively stationary cam shaft 2 on thevehicle in generally known manner. In this example, the hydraulic motorhas five radial cylinders 3, provided around the Wheel hub at equallyspaced intervals, in which hydraulic pistons (not shown) work inco-operation with the cam periphery on the cam shaft, again in generallyknown manner.

To provide for the flow and return of hydraulic pressure fluid to theaforesaid hub cylinders 3, supply and exhaust passages 4 and 5 areprovided axially through the cam shaft 2 and open into the outer camshaft end. These passages are then connected through the distributionvalve with radial flow and return passages 6 carried by the wheel huband leading to the respective cylinders 3.

The distribution valve is constituted, in this em'bodiment, by a statorblock 7 which is of circular plate-like form and is concentricallyattached to the outer end of the cam shaft 2 by means of a screw 8 orthe like. This stator block may be made of any appropriate materialhaving the requisite strength, one suitable material being that soldunder the trade name Mazak. The block has ports 9 therethrough which aredisplaced by 180 from one another and which extend from circularopenings in the rear block face, these openings being respectivelyregistered with the pressure and exhaust passages 4 and 5 through thecam shaft. To prevent or inhibit leakage, flexible sealing rings (notshown), may be provided at the junctions of the passage openings in thecam shaft end and the port openings in the rear block face.

The block ports extend in the axial direction through the block 7 fromthe rear face and open at their forward ends into the centres ofarcua-te recesses 9a formed in the front face of the block. Thesearcuate recesses may have a width which is equal to or rather less thanthe diameter of the rear port openings in the block, and each extendsover an angle of rather less than 180 around the front block face. Toprovide for smooth flow of pressure fluid, the recesses 9a are shapedinternally so that they funnel smoothly int-o communication with theblock ports 9.

The front face of the block through which the arcuate recesses 9a openhas an upstanding rim 1%) therearound having diametrically opposed slots10a therein, these slots being oifset by from the centres of the arcuaterecesses 9a. This slotted rim It in conjunction with an upstandingcentre boss 1% on the front block face, serves to position sealing meansagainst the front face of the stator block. These sealing means consist,in this embodiment, of two flexible scaling rings 11 of rubber orrubber-like synthetic plastic material such as Nitrile and a disc 12 oflow friction bearing material such as graphite nylon orpolytetrafluoroethylene. As shown, the sealing rings 11 are disposedrespectively around the rims of the two arcuate recesses 90 and arefaced by the overlying low friction disc 12, which has a centralaperture fitting over boss 10b and arcuate slots therethroughregistering with recesses 9a. The thickness of disc 12 is such that itstands slightly proud of the boss b and of the rim 10 around the statorface. To prevent rotation of the disc 12 relative to the rimmed statorface, diametrically opposed projections 12a are provided on the discwhich engage in the respective rim slots 10a. The width of the sealingrings 11 around the respective recesses is such that the angular extentof a recess 9a and associated sealing ring 11 is only slightly less than180, as can be seen most clearly. in FIGURE 4.

Co-operating with the stator block 7 as described is a distributionrotor which conveniently takes the form of a cylindrical block 13. Thisrotor block is, in the illustrated embodiment, arranged to seat in aconcentric recess in the outer face of the hub casing with the innermostend of the block positioned concentrically against the recessed outerface of the stator block and in rubbing substantially leak-proof contactwith the low friction disc 12. To locate the block 13 on the hub casingfor rotation therewith, bolts indicated diagrammatically at 13a may beemployed.

In this embodiment five flow and return ports 14 open through the innerend face of the distribution block 13, these flow and return ports beingcentered on the same radii as the stator block recesses 90. The flow andreturn ports are conveniently of slightly flattened form with roundedends and extend for a short distance axially through the distributionblock and thence outwardly through radial passages 15 to the blockperiphery. These radial passages opening through the block periphery arein turn arranged to register with the radial flow and return passages 6which connect with the outer ends of cylinders 3. Any appropriateleak-proof connection can, of course, be provided between the passages 6and 15.

.With the arrangement described, it will be appreciated that rotation ofthe hub will bring the ports 14 in the distribution block sequentiallyinto communication with the pressure and exhaust ports through thestator block, it being possible for more than one distribution blockport to be connected with a pressure or exhaust port via the appropriaterecess 9a at the same time. The presence of the sealing means betweenthe overlying faces of the stator and rotor blocks provides an effectiveseal as between the recesses 9a and, at the same time, prevents anysubstantial leakage as between the recesses in the stator block and theports in the rotor block.

In the second embodiment of the invention illustrated in FIGURES 6 to10, the distribution valve is shown as having a stator block 16 ofcylindrical form and bolted to the outer end of a cam shaft 17 by bolts18. The stator block 16 has axial pressure and exhaust ports 19 and 20opening from the rear face thereof and extending over approximately halfthe axial length of the block, these pressure and exhaust ports 19 and20 being again relatively displaced by 180 to register with pressure andexhaust passages 21 and 22 formed through the cam shaft. The inner endsof the pressure and exhaust ports 19 and 20 in the stator block openinto arcuate recesses 23 formed in the peripheral face of the block.These recesses are conveniently formed with inset locating channelsaround the rims thereof each containing sealing means 24 constituted,for example, by an endless flexible sealing ring with a facing strip oflow friction synthetic plastic bearing material such as nylon orpolytetrafluoroethylene. Each recess 23 and its seal 24 are togetherdimensioned to extend over only slightly less than 180 of the blockperiphery, whilst the thickness of the sealing means is such that thelatter will stand proud of the peripheral block surface.

To co-operate with the cylindrical stator block 16, a distribution rotorin the form of a concentric ported sleevev 25 is mounted around thestator block 16 in an opening 26 provided through the hub casing,coaxial with cam shaft 17. The rotor sleeve 25 is connected for rotationwith the hub by ,keys such as 27 and is conveniently retained within thehub opening by a cap 28 secured by bolts 29 to the hub body. Five radialports 30 are formed through the rotor sleeve in this embodiment andaxially positioned sequentially to register with the recesses 23. Again,the sealing means 24 serves to seal the two recesses 23 in the statorblock from one another and also to prevent or inhibit leakage betweenthe overlying faces of the stator and rotor. The ports 39 in the rotorconnect with fiow and return passages 31 which, in this embodiment, areformed in the hub casing. As in the previous embodiment, these passages31 connect, at their outer ends, with hydraulic hub cylinders.

The arrangement of the distribution valve as described in either of theforegoing embodiments, increases the tolerance allowed in manufacture ofthe valve parts, since the sealing means between the rotor and statorcan be made effective to seal off the pressure and exhaust ports in thestator, even when a slight play exists between the rotor and statormembers.

What is claimed is:

1. A hydraulic distribution valve having a stator block and a rotorarranged for rotatable mounting relative to the stator block, with afront face of said stator block opposed to a face of said rotor, sealingmeans'comprising flexible sealing rings faced with low friction bearingmaterial interposed between said overlying stator and rotor faces toprovide substantially sealed connections between the stator and rotor,said stator block being of circular plate-like form and having pressureand exhaust ports opening therethrough from a rear face to a front faceof said stator block, said pressure and exhaust ports being displacedfrom each other by approximately degrees, and said pressure and exhaustports extending from circular openings in the rear face of said statorto open through centers of arcuate recesses formed in the front face ofthe stator block, said arcuate recesses each extending over an angle ofless than 180 degrees around the front face of said stator block andbeing shaped internally to funnel smoothly into communication with thestator block ports, and the front face of said stator block furtherincluding an upstanding center boss and an upstanding edge rim forlocking said sealing means within said arcuate recesses with theflexible sealing rings of said sealing means being disposed around thelips of each said arcuate recesses, said low friction bearing materialof said sealing means being in the form of an overlying facing dischaving a center opening fitting over said center boss and having arcuateslots in said disc registering with the arcuate recesses of said statorblock said facing disc being disposed over said flexible rings, saidfacing disc standing above said edge rim and said center boss, and portsthrough the face of said rotor whereby the rotor ports are positioned toregister alternately with said stator recesses during relative rotationof the rotor to the stator.

2. A hydraulic distribution valve as claimed in claim 1, wherein thedistribution rotor is in the form of a cylindrical block which isrotatably mounted with an inner end face in concentric sliding contactwith the low friction bearing disc on the front stator block face, saidrotor inner end face having a plurality of ports disposed concentricallytherearound and centered on the same radii as the stator block recesses,the said rotor ports being extended axially through the rotor block fora short distance and thence outwardly through radial passages to theblock periphery.

3. A hydraulic distribution valve as claimed in claim 2, wherein the lowfriction bearing disc is held against rotation on the rimmed statorblock face by projections on the disc engaging in slots in the aforesaidrim.

4. A hydraulic distribution valve as claimed in claim 3, wherein thesaid bearing disc is made of graphite nylon.

5. A hydraulic distribution valve as claimed in claim 4, wherein theflexible sealing rings are made of rubber-like material.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS Dickson et a1 91-204 Peck 91-204 Mills et a1 277-92 62,373,443 4/ 1945 Armington 277-92 2,525,498 10/1950 Naylor et a1.103-161 2,557,508 6/1951 Leibing 103-161 SAMUEL LEVINE, PrimaryExaminer. FRED E. ENGELTHALER, Examiner.

1. A HYDRAULIC DISTRIBUTION VALVE HAVING A STATOR BLOCK AND A ROTORARRANGED FOR ROTATABLE MOUNTING RELATIVE TO THE STATOR BLOCK, WITHRESPECT FACE OF SAID STATOR BLOCK OPPOSED TO A FACE OF SAID ROTOR,SEALING MEANS COMPRISING FLEXIBLE SEALING RINGS FACED WITH LOW FRICTIONBEARING MATERIAL INTERPOSED BETWEEN SAID OVERLYING STATOR AND ROTORFACES TO PROVIDE SUBSTANTIALLY SEALED CONNECTIONS BETWEEN THE STATOR ANDROTOR, SAID STATOR BLOCK BEING OF CIRCULAR PLATE-LIKE FORM AND HAVINGPRESSURE AND EXHAUST PORTS OPENING THERETHROUGH FROM A REAR FACE TO AFRONT FACE OF SAID STATOR BLOCK, SAID PRESSURE AND EXHAUST PORTS BEINGDISPLACED FROM EACH OTHER BY APPROXIMATELY 180 DEGREES, AND SAIDPRESSURE AND EXHAUST PORTS EXTENDING FROM CIRCULAR OPENINGS IN THE EARFACE OF SAID STATOR TO OPEN THROUGH CENTERS OF ARCUATE RECESSES FORMEDIN THE FRONT FACE OF THE STATOR BLOCK, SAID ARCUATE RECESSES EACHEXTENDING OVER AN ANGLE OF LESS THAN 180 DEGREES AROUND THE FRONT FACEOF SAID STATOR BLOCK AND BEING SHAPED INTERNALLY TO FUNNEL SMOOTHLY INTOCOMMUNICATION WITH THE STATOR BLOCK PORTS, AND THE FRONT FACE OF SAIDSTATOR BLOCK FURTHER INCLUDING AN UPSTANDING CENTER BOSS AND ANUPSTANDING EDGE RIM FOR LOCKING SAID SEALING MEANS WITHIN SAID ARCUATERECESSES WITH THE FLEXIBLE RINGS OF SAID SEALING MEANS BEING DISPOSEDAROUND THE LIPS OF EACH SAID ARCUATE RECESSES, SAID LOW FRICTION BEARINGMATERIAL OF